LIHUE, Hawaii (AP) — Hawaii's governor declared a disaster for two islands on Tuesday after three days of relentless rains caused flooding and a sewage spill on Kauai, where officials were dealing with tree-blocked roads, closed schools and dangerous surf.

Gov. Neil Abercrombie's declaration includes Oahu, where Honolulu is located. A brown water advisory was issued on the island after two manholes overflowed and wastewater flowed into the ocean. There were also warnings of possible hail, lightning, rockslides and water-clogged roads.

Kauai schoolchildren were kept home Tuesday. A middle school was functioning as an emergency shelter, where 33 people spent the night Monday. The Hawaii chapter of the Red Cross said more than 50 others spent the night at three other shelters.

State workers in Honolulu on Tuesday continued to remove floating trash from the debris trap at the entrance to the Ala Wai small boat harbor. Cleanup began Monday after the weekend rains washed large amounts of trash into the Ala Wai canal.

The National Weather Service issued a flash flood watch for Kauai, Niihau and Oahu, as well as the islands of Lanai, Maui and Molokai.

A high surf warning was also in effect for the east shores of most islands in the archipelago. Forecasters said showers were likely for Wednesday with wind gusts as high as 24 mph.

Honolulu plans to temporarily close Hanauma Bay Nature Preserve on Wednesday because of the heavy rains and surface runoff.

Abercrombie's declaration allows for the activation of civil defense and other emergency functions, if necessary. It comes after Kauai Mayor Bernard Carvalho Jr. signed a disaster declaration on Monday.